The objective of this research is to determine the role of angiotensin II in the central regulation of blood pressure and the pathogenesis of hypertension. Studies will be carried out with brain cell cultures from normal and spontaneously hypertensive rats to characterize the angiotensin system in the brain, to determine the role of angiotensin receptors in the regulation of central angiotensin actions, to determine morphologic and quantitative relationships between angiotensin and catecholamines in the CNS, and to determine whether differences exist in angiotensin and catecholamine levels and distribution in the spontaneously hypertensive rat. Attempts will be made to identify alterations which may provide a marker for the transmission of genetically determined hypertension. Methods used in this research include cell culture, immunofluorescence, immunocytochemistry, cytochemical analysis, and ligand-binding analysis.